Searches in subdirectories for png files with names "frame-1.png", "frame-2.png"... and so on. Then makes a horizontal or vertical spritesheet out of the individual frames.

concatenate_imgs_in_subdirectories.bash

#!/bin/bash

#Directory setup: Individual images constituting one spritesheet must be by themselves in their own directory. 
# 	All images must be '.png' files with that extension in their name. 
#	In a spritesheet directory, the images must be name frame-1.png thru frame-LAST_FRAME_NUMBER.png
#utilizes ImageMagick for spritesheet creation





#copied from http://askubuntu.com/questions/179898/how-to-round-decimals-using-bc-in-bash
round()
{
echo $(printf %.f $(echo "scale=$2;(((10^$2)*$1)+0.5)/(10^$2)" | bc))
};


imgWidth(){

  WIDTH=$(convert $1 -print %w /dev/null)
  HEIGHT=$(convert $1 -print %h /dev/null)

  #do floating point division with the 'bc' command
  #I expect the images to be about 120 pixels. Thus use that to approximate. This may be wrong, and the output will need to be checked in Phaser
  NUM_FRAMES=$(bc -l <<< "$WIDTH / 120.0")
  NUM_FRAMES=$(round $NUM_FRAMES 10) #Round to nearest integer
  INDIVIDUAL_WIDTH=$(bc -l <<< "$WIDTH / $NUM_FRAMES")

  echo $INDIVIDUAL_WIDTH
}


imgHeight(){
  HEIGHT=$(convert $1 -print %h /dev/null)
  echo $HEIGHT
}


#arg1 is the output file path (with file name)
#arg2 is the path of the file to add
#arg3 is the frame # we're on
#arg4 is the -h or -v flag
concatImg(){
	HEIGHT=$(imgHeight "$2")
	WIDTH=$(imgWidth "$2")
	if [ "$4" == "-h" ] ; then
		montage "$2" -tile "$3"x1 -geometry "$WIDTH"x"$HEIGHT"+0+0 -background transparent "$1"
	elif [[ "$4" == "-v" ]] ; then
		montage "$2" -tile 1x"$3" -geometry "$WIDTH"x"$HEIGHT"+0+0 -background transparent "$1"
	else 
		echo "compact spritesheets not supported. Add it in yourself, or add a '-h' or '-v' argument"	
	fi
}


#argument 1 is the parent directory of images
#arg 2 is the output directory
#argument 3 is '-v' (vertical) or '-h' (horizontal), the type of spritesheet that will be made
concatenateImgs() {

		echo "Autocropping each png to remove empty space around edges before making them into a spritesheet"
		for entry in "$IMG_DIR"/*.png
		do
			echo "    Cropped $entry"
			convert $entry -trim $entry
		done
		
		

		#echo "making spritesheet out of $NUM_PNGS_IN_THIS_DIR images"
		echo "making spritesheet out of all images"
		FRAME_NUM=1
		for entry in "$IMG_DIR"/*.png
		do
			if [ "$FRAME_NUM" = 1 ] ; then
				cp "$entry" "$2"
			else
				echo "2 SEEN!!!"
				concatImg "$2" "$entry" $FRAME_NUM $3
			fi	
			FRAME_NUM="$(($FRAME_NUM+1))"
		done

		#double check by trimming after making spritesheet too
		convert $2 -trim $2
}











echo $0


read -e -p "Directory with images:" IMG_DIR
IMG_DIR="${IMG_DIR/#~/$HOME}" #substitute a '~' at the beginning of string with $HOME. http://stackoverflow.com/questions/38364603/using-a-variable-directory-name-in-bash-prevents-me-from-seeing-files-in-that-di/38364929#38364929

#read -e -p "Output directory:" OUTPUT_DIR
OUTPUT_PATH="$HOME/Desktop/spritesheet.png"


concatenateImgs "$IMG_DIR" "$OUTPUT_PATH" -h